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Cooling field and temperature dependent exchange bias in spin glass/ferromagnet bilayers.

Rui WB, Hu Y, Du A, You B, Xiao MW, Zhang W, Zhou SM, Du J - Sci Rep (2015)

Bottom Line: Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards.In the meanwhile, HFC variation has weak effects on HC.Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.

ABSTRACT
We report on the experimental and theoretical studies of cooling field (HFC) and temperature (T) dependent exchange bias (EB) in FexAu1-x/Fe19Ni81 spin glass (SG)/ferromagnet (FM) bilayers. When x varies from 8% to 14% in the FexAu1-x SG alloys, with increasing T, a sign-changeable exchange bias field (HE) together with a unimodal distribution of coercivity (HC) are observed. Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards. In the meanwhile, HFC variation has weak effects on HC. By Monte Carlo simulation using a SG/FM vector model, we are able to reproduce such HE dependences on T and HFC for the SG/FM system. Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

No MeSH data available.


Related in: MedlinePlus

(a) The M-H hysteresis loops measured under HFC = 0.2 kOe and 50 kOe at T = 2 K for a Fe11Au89(50 nm)/FeNi(5 nm) sample, (b) the calculated M-H hysteresis loops under HFC = 0.2 kOe and 50 kOe at T = 2.6 K for the SG/FM bilayers, and the experimental (c) and calculated (d) cooling field dependences of low-temperature HE and HC.
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f4: (a) The M-H hysteresis loops measured under HFC = 0.2 kOe and 50 kOe at T = 2 K for a Fe11Au89(50 nm)/FeNi(5 nm) sample, (b) the calculated M-H hysteresis loops under HFC = 0.2 kOe and 50 kOe at T = 2.6 K for the SG/FM bilayers, and the experimental (c) and calculated (d) cooling field dependences of low-temperature HE and HC.

Mentions: At low T, the HFC dependence of HE is also interesting. The experimental and simulation results as shown in Fig. 4 indicate that the entire M-H hysteresis loop moves rightwards with a strong enough HFC. As a result, HE decreases with increasing HFC while HC is insensitive to HFC. Furthermore, there is a slight vertical magnetization shift observed experimentally under strong HFC, arising from a minor magnetization in the FeAu SG. Increase in HE at low HFC (≤1 kOe) is very small because saturation in the FeNi (FM) has not been achived.


Cooling field and temperature dependent exchange bias in spin glass/ferromagnet bilayers.

Rui WB, Hu Y, Du A, You B, Xiao MW, Zhang W, Zhou SM, Du J - Sci Rep (2015)

(a) The M-H hysteresis loops measured under HFC = 0.2 kOe and 50 kOe at T = 2 K for a Fe11Au89(50 nm)/FeNi(5 nm) sample, (b) the calculated M-H hysteresis loops under HFC = 0.2 kOe and 50 kOe at T = 2.6 K for the SG/FM bilayers, and the experimental (c) and calculated (d) cooling field dependences of low-temperature HE and HC.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4562234&req=5

f4: (a) The M-H hysteresis loops measured under HFC = 0.2 kOe and 50 kOe at T = 2 K for a Fe11Au89(50 nm)/FeNi(5 nm) sample, (b) the calculated M-H hysteresis loops under HFC = 0.2 kOe and 50 kOe at T = 2.6 K for the SG/FM bilayers, and the experimental (c) and calculated (d) cooling field dependences of low-temperature HE and HC.
Mentions: At low T, the HFC dependence of HE is also interesting. The experimental and simulation results as shown in Fig. 4 indicate that the entire M-H hysteresis loop moves rightwards with a strong enough HFC. As a result, HE decreases with increasing HFC while HC is insensitive to HFC. Furthermore, there is a slight vertical magnetization shift observed experimentally under strong HFC, arising from a minor magnetization in the FeAu SG. Increase in HE at low HFC (≤1 kOe) is very small because saturation in the FeNi (FM) has not been achived.

Bottom Line: Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards.In the meanwhile, HFC variation has weak effects on HC.Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

View Article: PubMed Central - PubMed

Affiliation: National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, P. R. China.

ABSTRACT
We report on the experimental and theoretical studies of cooling field (HFC) and temperature (T) dependent exchange bias (EB) in FexAu1-x/Fe19Ni81 spin glass (SG)/ferromagnet (FM) bilayers. When x varies from 8% to 14% in the FexAu1-x SG alloys, with increasing T, a sign-changeable exchange bias field (HE) together with a unimodal distribution of coercivity (HC) are observed. Significantly, increasing in the magnitude of HFC reduces (increases) the value of HE in the negative (positive) region, resulting in the entire HE∼T curve to move leftwards and upwards. In the meanwhile, HFC variation has weak effects on HC. By Monte Carlo simulation using a SG/FM vector model, we are able to reproduce such HE dependences on T and HFC for the SG/FM system. Thus this work reveals that the SG/FM bilayer system containing intimately coupled interface, instead of a single SG layer, is responsible for the novel EB properties.

No MeSH data available.


Related in: MedlinePlus